Can you roast two beef tenderloins (6 & 7) in one big pan? Also is 1/2 lb per person enough?

Yes you can roast 2 tenderloins in one pan. And you will need a meat thermometer to let you know when they are done to your liking. Here is our all time favorite recipe for beef tenderloin and I have found taste trumps quantity.
http://food52.com/recipes...

Roasting two together is fine - as long as the pan is large enough so they're not crowded, and air can circulate around each one. And yes, I usually figure 1/2 lb. per person - you could probably do slightly less, but that's enough for a generous portion, and/or a few slices to eat deliciously cold the next day.